Within the field of internal grooving and boring of a rotating metal workpiece, cutting inserts manufactured from a hard material, namely cemented carbide, may be secured to a tool holder in many different ways.
U.S. Pat. No. 3,289,273 discloses a cutting tool assembly comprising a tool holder with a longitudinal axis and a removable tool head having a solid carbide cutting insert brazed onto the tool head. The tool holder includes a seat with a dovetailed groove having two side surfaces inclined at an acute angle to the seat surface, and the tool head includes a seating surface with a dovetailed slide member having two complementary side surfaces, where each of these surfaces is accurately machined so that the tool head will be automatically oriented in a direction along the longitudinal axis when mounting the tool head onto the tool holder. The slide member is slid into the groove to a position where a threaded orifice in the tool holder is approximately aligned with a tapered recess in the tool head, before a set screw within the threaded orifice is tightened against the tapered recess to complete the orientation of the tool holder in a direction perpendicular to the longitudinal axis.
This cutting tool assembly attempts to provide a swift and accurate means for re-orienting the tool head following removal from the tool holder, although it is suggested that there may be difficulties initially locating the slide member within the dovetail groove. A disadvantage of the first embodiment of this cutting tool assembly is that a major cutting force component tangential to a rotating workpiece is directed generally perpendicular to and away from the tool holder seat surface.
U.S. Pat. No. 4,102,591 discloses a cutting tool comprising a tool holder with a longitudinal axis and a solid carbide cutting insert with a cantilevered cutting portion removably secured within the tool holder. An outer end portion of the tool holder includes a recess with a flat bottom surface inclined at approximately 45° to the longitudinal axis and a side surface perpendicular to the bottom surface. The cutting insert also has perpendicular bottom and side surfaces which are positioned against the bottom and side surfaces of the recess, respectively, and a sloping side surface which is positioned opposite and at an acute angle to the bottom and side surfaces of the recess. A retaining screw interfacing with a threaded opening perpendicular to the bottom surface of the recess has a head which is tightened against the sloping side surface of the cutting insert to direct clamping force components towards the bottom and side surfaces of the recess. Also, during a cutting operation, cutting forces acting on the cutting end portion of the cutting insert are directed towards the bottom and side surfaces of the recess.
This cutting tool employs a relatively large solid carbide cutting insert providing both a means of attachment to the tool holder and a single cutting end portion, which is disadvantageous when considering the relative expense of solid carbide tooling.
U.S. Pat. No. 7,240,593 discloses a cutting apparatus comprising a bar device mount of primarily cylindrical shape with a longitudinal axis and a detachably fastened tool head with a pocket that receives a cutting insert. The bar device mount has a front mating end perpendicular to the longitudinal axis with a projection having two long vertical surfaces and 45° inclined top and bottom surfaces, each parallel to the longitudinal axis. The tool head has a rear mating end with a recess which is located on the projection by interfitting surfaces and fastened by a head screw engaged within a screw-receiving orifice shared by the head and mount and inclined at an acute angle to the longitudinal axis.
This invention has a disadvantage in that the cutting apparatus provides only moderate precision of tool head positioning relative to the mount in a vertical direction. Another disadvantage is the possibility that the tool head may easily separate and fall from the mount when the head screw is removed.